AITA for not saying Thank you one time?

I’m currently dealing with some really heavy family problems with my brother and sister-in-law, and it reached a point this weekend where I am just completely done. My love language is gift-giving. Whenever I get them something, I always make sure it’s tailored specifically to what they like. But almost every single time, it comes back to bite me. They turn it into an argument, get mad at me, and break me down. Meanwhile, I make a point never to touch or eat anything of theirs unless they specifically hand it to me and tell me it’s mine. I’ve reached a point where I just stopped making or getting anything for them altogether. When I bake cookies or treats now, I take them to my coworkers and friends instead. I feel like it's better this way because they actually appreciate the gesture, and I genuinely love making people smile. But because I stopped bending over backward, they’ve started ignoring me. This past weekend was terrible: Overstepping boundaries: I went shopping with my mom and was in a great mood until they randomly showed up at the same store. My stomach dropped and I literally froze. My mom basically forced me to go with them even though I didn’t want to. Damned if I do, damned if I don't: My brother asked if I wanted a drink, and I said, "No, I'm good." They ordered me something anyway against my wishes. Then they got mad and claimed I didn't respond when I explicitly did. Lack of respect: They don't even ask me if I can attend family events (like my cousin's upcoming wedding) or check if it works with my job they just expect things or force them on me. The final straw was getting told horrific things that I'm "useless," "shouldn't be alive," and "don't deserve anything nice", all because of a tiny detail like not saying "thank you" one single time in a forced situation. Cruel words like that say everything about their toxicity and nothing about my actual worth. I knew this day would come. It sucks and it hurts, but I am officially done being a people-pleaser. I am done seeking approval or giving attention to people who only use it to get me in trouble for things I didn't even do. Pulling back and protecting my own peace isn't being petty, it's necessary. I'm choosing to save my kindness, my baking, and my energy for the people in my life who actually value and respect me.

I think I might be TA for just not being nice to them like I used to be. I even left a couple group chats that had them in them (3 person group chat).